Sunshade device for motor-vehicles, with shape memory actuator

ABSTRACT

A sunshade device comprises a sunshade in the form of a roller blind forming part of a roller-blind device, comprising a supporting structure, a shaft for rolling of the sunshade blind, mounted so that it can rotate on the aforesaid supporting structure, and a shape-memory actuator device for causing displacement of the blind from the rolled-up condition to the distended condition.

BACKGROUND OF THE INVENTION

The present invention relates to a sunshade device for motor vehicles,comprising a sunshade that can be displaced between an inoperativeposition and an operative position with respect to a supportingstructure, and a shape-memory actuator for controlling displacement ofthe sunshade from its inoperative position to its operative position.

A device of the type referred to above is described and illustrated inthe document No. JP-A-62 006824. In the case of said known device, thesunshade is in the form of a panel guided in a slidable way between aninoperative position where it is retracted within a casing and anextracted operative position. On account of the dimensions of thesunshade, the casing that receives it in the inoperative condition has arelatively large encumbrance in the longitudinal direction of the motorvehicle. Said aspect constitutes a drawback, particularly in the case ofvehicles equipped with sunroof with window. In this case, in fact, thefront cross member of the roof, which delimits at the front the openingof the window, must present a dimension in the longitudinal direction ofthe motor vehicle that is relatively large, which makes it impossiblefor the driver and the passenger sitting in the front seat of the motorvehicle to enjoy fully the advantages of the window present on the roof.Said circumstance is highlighted in FIG. 1 of the annexed plate ofdrawings, which shows a partial view of a motor vehicle 1, equipped witha windscreen 2 and a roof 3 with a window 4 delimited at the front by across member 5. In the case of application of the device according tothe known art, the cross member 5 has, as clearly illustrated in FIG. 1,a dimension in the longitudinal direction A of the motor vehicle that isrelatively large, in so far as each of the sunshades 6 must be received,in its own inoperative condition, within said cross member 5.Consequently, the front edge 7 of the window 4 made in the roof 3 issensibly retracted, a fact which, as has been said, does not enable thedriver of the motor vehicle and the passenger sitting in the front seatto enjoy fully the advantages of the window on the roof.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to overcome the aforesaiddrawback.

A further purpose is to provide a sunshade device with shape-memoryactuation that is simple, has small overall dimensions, and is efficientand quiet during operation.

With a view to achieving said purpose, the subject of the invention is asunshade device having the characteristics referred to at the start ofthe present description and further characterized in that the aforesaidsunshade is constituted by the blind of a roller-blind device,comprising a supporting structure and a shaft on which the blind isrolled up, which is mounted on the supporting structure so that it canrotate, said shape-memory actuator comprising at least one shape-memoryelement that can be activated for controlling movement of the rollerblind from the rolled-up condition to the distended condition.

Thanks to the characteristic indicated above, in the condition where itis installed on the motor vehicle, the device according to the inventionhas small overall dimensions in the longitudinal direction of the motorvehicle, which enables sensible reduction in the transverse dimension ofthe front cross member of the roof panel with consequent advantages inthe case where the vehicle is equipped with a sun roof with window. Ofcourse, the invention can in any case be applied with practicaladvantage also on motor vehicles not provided with sunroof with awindow.

The shape-memory actuator can be of the type in which a shape-memoryactuator element controls the movement of the sunshade only from itsinoperative position to its operative position, engagement means beingprovided for withholding the sunshade in its operative position oncethis has been reached so as to enable de-activation of the shape-memoryelement. In the case of said solution, there are provided means forde-activating the engagement means and elastic means that bring back thesunshade into its inoperative position.

In a second solution, a first shape-memory actuator element and a secondshape-memory actuator element are provided for controlling movement ofthe sunshade into the operative position or into the inoperativeposition, respectively.

In a third solution, the shape-memory actuator is of a bistable type,i.e., of the type in which each successive activation of theshape-memory actuator brings about movement of the sunshade from theinoperative position into the operative position or vice versa, thesunshade remaining each time in the position reached after de-activationof the actuator.

The shape-memory element is preferably of the type that can be activatedby electrical-supply means, which cause passage of an electric currentthrough the shape-memory element, so as to heat it by the Joule effectbeyond its transition temperature.

According to a further characteristic of the invention, the roller blindconstituting the sunshade has two longitudinal edges provided with astiffening element in such a way that, in the distended condition, thesunshade has a substantially rigid and self-bearing configuration andprojects in cantilever fashion from the roller-blind casing.

The supporting structure of the roller blind is in turn connected to afixing bracket by means of an articulated joint, which enablesorientation of the sunshade in any desired position, for example in sucha way as to lay it out parallel to the windscreen or parallel to a sidewindow of the motor vehicle or in order adjust the angle of inclinationof the blind in its distended configuration.

In an example of embodiment, the shape-memory actuator comprises anelongated shape-memory element wound within a casing and made in such away as to control rotation of the shaft for rolling-up of the blind viaa gear transmission. The wound shape-memory device can be, for example,of the type forming the subject of the copending European patentapplication No. 06425135.8 filed in the name of the present applicant.

In a variant, the shape-memory actuator can comprise one or moreshape-memory wires arranged so as to bring about rotation of respectivepulleys connected in rotation to arms for supporting the end edge of theblind, which can oscillate between a retracted position and an extractedposition in which they cause unrolling of the blind from the rollerdevice.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will emerge fromthe ensuing description with reference to the annexed plate of drawings,which are provided purely by way of non-limiting example and in which:

FIG. 1 is a partial perspective view of a motor vehicle equipped with asunshade shape-memory-actuator device according to the known art;

FIG. 2 is a view corresponding to that of FIG. 1, which shows a motorvehicle provided with a device according to the invention;

FIG. 3 is a schematic perspective view of the device according to theinvention, in the inoperative condition;

FIG. 4 is a perspective view of the device of FIG. 2, in the operativecondition;

FIGS. 5, 6 and 7, 8 illustrate the aforesaid inoperative and operativeconditions of the device of FIGS. 3 and 4 in a front view and in a sideview, respectively;

FIGS. 9 and 10 are perspective views of a second embodiment of thedevice according to the invention in the inoperative condition and inthe operative condition, respectively; and

FIGS. 11, 12 and 13, 14 show the aforesaid two operative conditions ofthe device of FIGS. 9 and 10 in a front view and in a side view,respectively.

DETAILED DESCRIPTION OF THE INVENTION

As has already been described above, FIG. 1 shows the application of asunshade shape-memory-actuator device according to the known art, forexample of the type illustrated in the document No. JP-A-62 006 824,applied to a motor vehicle equipped with a sunroof with window. Asdiscussed above, in said application the disadvantage due to theencumbrance of the device in the longitudinal direction A of the motorvehicle is evident, in that it entails a very retracted positioning ofthe front edge 7 of the window 4 of the roof.

FIG. 2 illustrates a similar application of a device provided inaccordance with the teachings of the present invention. In this case,the front cross member 5 of the roof panel 3 of the motor vehicle has avery small dimension in the longitudinal direction A, which entails avery advanced positioning of the front edge 7 of the window 4 made inthe roof 3. In this way, also the driver and the passenger sitting inthe front seat can enjoy fully the advantages of the window 4.

As may already be seen schematically from FIG. 2, the motor vehicle isequipped with one or more sunshade devices 8. In the case in point, twodevices are provided, designed to be used respectively by the driver andby the passenger occupying the front seat adjacent to the driver. Thereis nothing, however, to rule out similar devices possibly beingprovided, for example, in areas corresponding to the rear side windowsso as to be used by the passengers occupying the rear seats of the motorvehicle.

Each device 8 is substantially constituted by a roller blind supportedin an orientable way by a bracket fixed to the structure of the motorvehicle.

With reference to the embodiment illustrated in FIGS. 3-8, the sunshadeproper, designated by the reference number 6, is constituted by theroller blind of a roller-blind device. The blind 6 can be made of fabricor of a synthetic material and incorporates along its longitudinal edgestwo flexible-metal strips 6a, which wind within the casing of the devicein the rolled-up condition of the blind, but have in any case astiffness sufficient to maintain the blind 6 substantially in tensionand rigid, i.e., self-bearing, in its distended condition in cantileverfashion outside the roller-blind casing.

As may be seen in particular from FIGS. 5 and 6, the blind 6 rolls up ontwo end rollers 9 carried by a winding shaft 10, which is supported, insuch a way that it can rotate, within a cylindrical casing 11 having aslit 12 from which the blind 6 comes out. Rotation of the winding shaft10 is driven by a shape-memory actuator 13 of which the drawings showthe outer casing. The shape-memory actuator 13 is of the type designedto set in rotation a disk 14 by means of a elongated shape-memoryelement, for example, in the form of a wire or strip, wound in a spiralor else in a helix. An actuator device of this type forms the subject ofthe copending European patent application No. 06425135.8 filed in thename of the present applicant. Basically, it envisages a wire made ofshape-memory material wound in a helix on a rotatable body and havingone end fixed on said body and the opposite end connected to a fixedstructure. The actuator device comprises electrical-supply means thatcan be actuated by the driver by means of a control pushbutton forexample adjacent to the device 8, which causes the elongatedshape-memory element to be traversed by electric current. Following uponpassage of current, the elongated shape-memory element undergoes heatingby the Joule effect above its transition temperature, so that theelement tends to shorten, thus setting the disk-like body on which it iswound in rotation. Rotation of the disk 14 gives rise to a correspondingrotation of a toothed sector 15, which is rigidly connected to the disk14 and rotates therewith around the respective axis of rotation 16. Thetoothed sector 15 in turn meshes with a sprocket wheel 17 (FIGS. 7 and8) carried by one end of the winding shaft 10.

Thanks to the arrangement described above, activation of theshape-memory element causes rotation of the shaft for rolling-up of theblind from the condition corresponding to the inoperative position ofthe blind (FIGS. 3 and 5, 7) to the operative position (FIGS. 5 and 6,8).

As already mentioned above, activation of the shape-memory actuatordevice 13 can be controlled by the user by operating a pushbutton,designated as a whole by 18 in FIG. 3, which transmits a signal to anelectronic control unit 19, which provides electrical supply to theshape-memory actuator device 13.

In one embodiment, the device can be envisaged so as to maintain theblind 6 in the distended condition as long as the electrical supply ofthe shape-memory actuator is maintained. As said supply ceases, whichcan be obtained once again by actuating the control pushbutton 18, theshape-memory element cools down and returns into its original condition,and retraction of the blind 6 in the rolled-up condition is obtained bymeans of elastic-return means, for example in the form of a spiralspring associated to the disk 14 itself of the shape-memory actuator orto the winding roller 10.

However, according to the invention, it is considered advantageous toensure that the blind 6 will remain in its operative extracted positionwithout requiring maintenance of the electrical supply of theshape-memory actuator. The simplest way to obtain this result is to usea shape-memory actuator of a bistable type. An actuator of this typehas, for example, formed the subject of the European patent No. EP-B-1241 351 filed in the name of the present applicant. Basically, bistableoperation is obtained by associating to the member driven by theshape-memory element either elastic means that tend to bring back thedriven member into a resting position or a device for clamping thedriven member in the operative condition into which it is brought whenthe shape-memory element is activated, the arrangement being such that,once the driven member has been clamped in its operative condition, asubsequent temporary activation of the shape-memory element causesde-activation of the aforesaid clamping device. In this way, the drivenmember is normally kept in its resting position by the aforesaid elasticmeans. Starting from this condition, if the shape-memory element isactivated, the driven member is displaced into its operative condition,against the action of the aforesaid elastic means, until it causesengagement of the clamping device, after which the driven member remainsin its operative condition even if the shape-memory element isde-activated. A subsequent activation of the shape-memory element causesde-activation of the clamping device and consequent return of the drivenmember into its resting position as a result of the elastic returnmeans.

As an alternative to said solution, a first shape-memory element may beprovided for causing displacement of the driven member from its restingposition to its operative position, where it is clamped by an engagementdevice so as to enable de-activation of the first shape-memory element,as well as a second shape-memory element, which is designed to causede-activation of the engagement device so as to bring about return ofthe driven member into its resting position under the action of elasticreturn means.

To return to the embodiment illustrated in FIGS. 3-8, the entirestructure constituted by the casing 11 and the casing 13 connected atone end of the casing 11 is connected, by means of a ball-and-socketjoint 20 located at the centre of the casing 13, to an L-shapedsupporting pin 21, projecting from a bracket 22 provided with holes 23for screws for fixing the bracket 22 to the structure of the motorvehicle. Moreover associated to the casing 13 is a gripping handle 13a,which enables manual orientation of the entire structure of the deviceexploiting the freedom of movement afforded by the ball-and-socket joint20. In this way, the user can easily position the device 8 in the mostconvenient way, for example in a position corresponding to thewindscreen of the motor vehicle or of a side window. In addition, theball-and-socket joint 20 affords also the possibility of adjusting theangular position of the slit 12 from which the blind 6 comes out so asto vary, in the distended condition of the blind, the angle ofinclination of the blind itself.

A further advantage of the device according to the invention is that itis always and in any condition manually controllable. For example, inthe case of the embodiment described above with reference to FIGS. 3-8,at any moment the user can grip the end edge of the blind 6, when thisis extracted in the condition of FIG. 4, and push it so as to cause itto enter within the casing. Otherwise, the blind can also be unrolledmanually outside the casing. FIGS. 9-14 refer to a second embodiment. Insaid figures, the parts that are common to the ones of FIGS. 3-8 aredesignated by the same reference numbers. The main difference withrespect to the embodiment described previously lies in the way theshape-memory actuator means are made. This embodiment does not envisagean actuator with wound shape-memory element, but rather two shape-memorywires 24 (see FIGS. 11 and 12) are provided, which run within the casing11. Each wire 24 has one end 24 a fixed to the casing 11, and theopposite end engaged around a pulley 25 mounted so that it can rotateabout an axis 26 on the structure of the casing 11 (see also FIGS. 13and 14). Each pulley 25 supports in rotation a flattened metal arm 27having one end connected in rotation with the respective pulley 25 andthe opposite end articulated in 28 on a slider 28a which is able toslide along a cross member 29 (see FIG. 10) fixed to the free edge ofthe blind 6. Activation of the two shape-memory wires 24 causes rotationof the two pulleys 25 and consequent oscillation of the two arms 27 fromthe retracted and mutually aligned condition illustrated in FIGS. 9 and11 into the condition where they are rotated through 90° of FIGS. 10 and12.

Associated to the pulleys 25 are, for example, spiral springs, tendingto bring back the arms 27 into the retracted condition illustrated inFIG. 9. In a way similar to what has been described above with referenceto the first embodiment, once the shape-memory element is activated, itcan be kept in said condition by maintaining the electrical supply ofthe shape-memory element. Upon ceasing of the electrical supply, thesprings associated to the pulleys 25 bring back the blind into theretracted condition. Once again in a way similar to what has beendescribed with reference to the first embodiment, it is, however,possible to provide a device for engaging the blind in the distendedcondition, which enables the blind itself to be kept in said conditioneven after de-activation of the shape-memory element. In this case, itis necessary to provide means for de-activation of the engagement devicein order to bring the blind back into the retracted condition. Saidresult can be obtained, for example, by providing a further shape-memoryelement (not illustrated), which is activated by the user when hepresses the pushbutton 18 for governing rolling of the blind 6.

Of course, without prejudice to the principle of the invention, thedetails of construction and the embodiments may vary widely with respectto what is described and illustrated herein purely by way of example,without thereby departing from the scope of the present invention.

1. A sunshade device for motor vehicles, comprising a sunshade that canbe displaced between an inoperative position and an operative positionwith respect to a supporting structure, and a shape-memory actuator forcontrolling displacement of the sunshade from its inoperative positionto its operative position, said device being characterized in that saidsunshade is constituted by a blind of a roller-blind device, comprisinga supporting structure and a shaft for rolling-up of the blind, mountedso that it can rotate in the supporting structure.
 2. The sunshadedevice according to claim 1, wherein the shape-memory actuator isprovided for controlling movement of the sunshade only from itsinoperative position to its operative position, said device furthercomprising: engagement means for withholding the sunshade in itsoperative position once this has been reached so as to enablede-activation of the shape-memory actuator element; means forde-activation of the aforesaid engagement means; and elastic means thatbring back the sunshade into its inoperative position.
 3. The sunshadedevice according to claim 1, wherein a first shape-memory actuatorelement and a second shape-memory actuator element are provided forcontrolling movement of the sunshade into its operative position andinto its inoperative position, respectively.
 4. The sunshade deviceaccording to claim 1, wherein the shape-memory actuator is of a bistabletype, designed to cause at each successive activation a movement of thesunshade from the inoperative position to the operative position, orvice versa.
 5. The sunshade device according to claim 1, wherein theshape-memory actuator comprises: a shape-memory element wound around arotatable disk, having one end connected to said rotatable disk and theopposite end connected to a fixed structure; means for electrical supplyof said shape-memory element, designed to cause a heating of saidshape-memory element beyond the transition temperature so as to bringabout shortening thereof, with a consequent rotation of the aforesaiddisk-like body on which the shape-memory element is wound; and a geartransmission for transmitting rotation of the aforesaid disk of theshape-memory actuator element to the shaft for rolling-up of the blind.6. The sunshade device according to claim 1, wherein said shape-memoryactuator comprises a pair of shape-memory wires that can be activatedfor controlling rotation of two oscillating arms, each having one endsupported in a rotatable way by the supporting structure of theroller-blind device and the opposite end connected in an articulated wayto a slider that can slide along a cross member fixed to the free edgeof the blind, in such a way that said oscillating arms are displaceablebetween an aligned retracted condition, corresponding to the rolled-upcondition of the blind, and a condition where they are rotated outwards,in which they cause unrolling of the blind.
 7. The sunshade deviceaccording to claim 1, wherein said blind is made of fabric or offlexible plastic material and has two longitudinal edges englobing twometal wires or strips sufficiently flexible to enable rolling-up withinthe casing of the roller-blind device in the rolled-up condition of theblind, but sufficiently rigid to bestow upon the blind a rigid andself-bearing condition, in the distended condition of the blind.
 8. Thesunshade device according to claim 1, wherein the supporting structureof the roller blind is connected to a bracket to be recured thestructure of the motor vehicle via a ball-and-socket joint.
 9. Thesunshade device according to claim 8, wherein the aforesaid articulatedjoint is provided in such a way as to maintain the casing of theroller-blind device clamped in any selected orientation and is inparticular shaped in such a way as to enable an adjustment of theinclination of the plane of the blind in the distended condition. 10.The sunshade device according to claim 1, wherein it comprises means foractivation of the shape-memory actuator, comprising a controlpushbutton, an electronic control unit, which activates a circulation ofelectric current through the shape-memory actuator following uponoperation of the control pushbutton.